I don't know exactly how the moorings are set up in Echo bay. Linear mooring means that all of the boats are lined up, and not fee to swing on a single point mooring. For example if the boat is moored with a bow and stern line, this is a linear mooring.
There are several kinds of this type. One can have a single anchor for each boat's bow and stern. Many will use the stern of the boat ahead of it for the bow of the next boat down the line. This system is also used in piling mooring, where one boat uses a piling for its stern, the next boat uses that piling for its bow. There is also the "string line" type of mooring--such as used at Catalina near the shore--or even in the med, with huge battle ship chains. In this mooring, there is a rope or chain in the center, and boats tie off on each side. There is also a stern anchor, or stern chain, which the stern line is attached to, and thus all of the boats are perpendicular to this "string line"on both sides of it.
You can also describe a dock as having linear mooring, which all boats tie along side, vs Med mooring, where the bow is anchored out--or out to a mooring XX feet from a sea wall, and then stern lines taken to the sea wall or dock--in the latter many more boats can be accommodated at a dock than along side.